The Advanced Vitrification System Improvements (AVSI) is an improved method for filling a disposable canister with vitrified waste and glass making frit (hereinafter referred to as xe2x80x9cwastexe2x80x9d) starting with a waste that is cooler than its melting point. The present invention relates generally to a process for vitrifying waste, such as nuclear waste, in a disposable canister.
The disclosure of U.S. Pat. No. 5,678,237, which describes a canister and related method of in-situ vitrification of waste materials in a disposable canister, is incorporated herein by reference. Also the disclosure of U.S. Pat. No. 6,283,908, which describes a method of filling a disposable canister with vitrified waste, is incorporated herein by reference. Referenced U.S. Pat. No. 5,678,237 is for a disposable canister with an inner container, which serves as a crucible, and an outer container. The outer container serves as the traditional disposal container typically made of steel. The outer container is usually insulated from the inner container. The inner container is typically made of graphite.
In referenced U.S. Pat. No. 5,678,237, waste is added to a module comprised of an inner container an outer container and insulation therebetween. An electrified induction coil sends magnetic flux through the outer container and insulation and preferentially heats the inner container, serving as the crucible. By this process, the waste is heated until it is melted. In referenced U.S. Pat. No. 6,283,908, waste is added incrementally and heated zonally. In both of the referenced patents, the waste is then allowed to cool into a solid vitrified product. In both referenced patents, the process involves the pre-assembly of an inner container and an outer container with insulation therebetween. The process of the referenced patents can be simplified and more volume made available for vitrified waste using the AVSI invention described herein.
Accordingly, the AVSI invention is an improvement over the referenced patents.
The AVSI invention improves the method of the referenced patents xc3xa2xcex5xe2x80x3 (1) by vitrifying waste in a crucible while the crucible is separate and apart from the outer container; (2) by eliminating the need to cool the outer container during the vitrification process because the outer container is not subjected to any heating during the vitrification process; and (3) by adding a step which would assemble the canister, that is namely, inserting the crucible, that is, the inner container, into the outer container after the cool-down of the vitrified waste. The AVSI invention improves the disposable canister of the referenced patents by eliminating the insulation between the inner and outer containers and by enlarging the diameter of the crucible to fill the volume within the outer container created by removal of the insulation, so that the disposal canister can contain a larger volume of waste.